The invention relates to a molding machine for making flaskless molds. The molding machine has two molding flasks, which are movable back and forth on a model plate carrier which in turn is movable in and out between the two molding flasks, and a hollow machine frame which receives the pourable molding material. The molding flasks are enclosed by a rectangular frame which absorbs the reactive forces occurring during the pressure-shaping process.
From U.S. Pat. No. 3,556,196, which is based on German Pat. Nos. 15 83 526 and 17 58 245, a molding machine for making flaskless molds is known, in which two molding flasks which are movable back and forth and a match plate carrier movable in and out between them are enclosed by a rectangular frame, the vertical columns of which absorb the reactive forces initiated during the compression of the molding material. However, these columns are massive in embodiment and have an exclusively static function.
From the same U.S. patent, a molding machine is also known has a hollow machine frame embodied in the shape of a C in the central vertical plane. The vertical bar is embodied as a connecting line for molding sand, and the bottom and top arms of the C serve to introduce the molding sand into the mold cavities of the two molding flasks in the closed position thereof. The two ends of the C arms facing one another are each enclosed by one annular cylinder, in each of which an annular piston subjected to a pressure medium reciprocates. The annular piston is connected in turn with a grate-like press die. These bar grates are subject to erosion by the molding sand flowing through them and accordingly experience heavy wear. In addition, two adjusting cylinders each are required for moving the two molding flasks. Since a machine frame in the form of an open C would break apart under the high pressures exerted, tie rods are furthermore required, as explained and illustrated at the beginning of the above-mentioned U.S. patent.
From German laid-open applications DE-OS Nos. 30 21 592 and 28 14 140, it is known to blow the molding sand into the mold cavities from containers for molding sand disposed laterally adjacent the molding flask or flasks.